Thread: Pressure Differences - ELD-M and ELD-X

Hey team,

Has anyone noticed significant pressure differences between the ELD-M and ELD-X of the same weight?

I've done some load development with the 162g ELD-M for my 7mm Rem Mag but have been given some 162g ELD-X to try out. So I'm wondering if it is safe to start roughly where I was with the ELD-M, or whether I need to start from scratch?

Book data is the same for both pills and the ever dangerous internet searching suggests most people are finding good results with both pills at 70 - 72g AR2217.

My accurate load with the ELD-M was 70.5g AR2217 with zero pressure signs (only went up to 71g because of availability at the time), so was thinking about starting at 70g and working up to 72g.

All suggestions welcome.

Cheers,
Elliott

I use x and m in my 6.5 same powder weights no pressure signs.

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Originally Posted by 25 /08 IMP

I use x and m in my 6.5 same powder weights no pressure signs.

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Thanks mate. Are they warm loads?

From what I have heard the m is softer than the x, so I would expect higher pressure with the x at the same powder charge, but I have no idea whether it’s enough to be an issue.
I would play it safe and start a bit lower and work up (which is recommended practice even when changing lot numbers of the same projectile - not that I do that myself).

ELD-X jackets are harder, which can push pressure up as they engrave onto the lands. It might be fine, but I would start a grain or two lower just in case.

The X hit pressure 1 -1.5gr earlier in my 284 over the M. Both 162gr

Originally Posted by stagstalker

The X hit pressure 1 -1.5gr earlier in my 284 over the M. Both 162gr

Awesome, that's great info thanks mate.

Cheers for all the other info too - will be load from 1.5g lower than the ELD-M load, which doesn't show pressure signs.

Originally Posted by Edunn

Thanks mate. Are they warm loads?

They are near max loads


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The eldx has a void behind the polymer tip, making it substantially (relatively speaking at least) longer than the eldm, hence the slightly higher BC with the eldx. You will need to adjust your seating die otherwise you will reduce the internal volume of the case under the bullet and increase the pressure.

Originally Posted by bang

The eldx has a void behind the polymer tip, making it substantially (relatively speaking at least) longer than the eldm, hence the slightly higher BC with the eldx. You will need to adjust your seating die otherwise you will reduce the internal volume of the case under the bullet and increase the pressure.

Where did you get that info? Just doing a comparison the 7mm 162eldx has a bc of 0.630 and the 162eldm has a bc of 0.670

huh, yea you are right. Comparing 30 cal 178grain (the ones I have been using), BC is .547 for eldm vs .552 for eldx. The eldx is noticably longer when comparing side by side. are the 7mm ones not?

Originally Posted by bang

huh, yea you are right. Comparing 30 cal 178grain (the ones I have been using), BC is .547 for eldm vs .552 for eldx. The eldx is noticably longer when comparing side by side. are the 7mm ones not?

Strange, 7mm 162gr X is noticeably larger then the M like you say but the BC of the 7mm M is definitely recorded as being higher.

Originally Posted by bang

huh, yea you are right. Comparing 30 cal 178grain (the ones I have been using), BC is .547 for eldm vs .552 for eldx. The eldx is noticably longer when comparing side by side. are the 7mm ones not?

Have not got my hot little hands on them yet. However the book data suggests the same COAL. Of course I'll do some dodgy measurements when I do receive them and try to figure out an appropriate seating depth myself.

Wasn't planning on trying everything exactly the same as the ELD-M - was merely looking for a powder starting point, given my rifle seems to handle above book max charges with the ELD-M perfectly fine.

I'd say the plan will be to start 1.5g lower than where I ended up with the ELD-M (which was below any sign of pressure).

Originally Posted by 25 /08 IMP

I use x and m in my 6.5 same powder weights no pressure signs.

Sent from my CPH1903 using Tapatalk

I've found the same even though the ELD-X is 3gr heavier. Exact pressure difference would no doubt be different.

The 30cal eldx 178 are quite a bit bigger than the 178eldms so can see why the eldx has a better bc even though it is negligible